This invention relates to an access door adapted to be installed on a building ceiling or wall for facilitating inspection and/or repair of facilities such as wiring, piping and air ducts installed within the building ceiling or wall.
When the access door is designed to be installed in a building ceiling, for example, the access door includes an outer framework adapted to be fitted in a rough opening formed in the ceiling and secured to the ceiling by an anchoring device, an inner framework fitted in an opening of the outer framework and pivotally connected to the outer framework by pivot pins and pin-supports, and a cover plate fixed to the inner framework for closing the opening thereof. In this way a cover, that is to say, a door, of the access door is made up of the inner framework and the cover plate, and the cover is locked to the outer framework by a cremone locking means (casement window bolt type lock) when the cover closes the opening in the outer framework, and the cover is moved downwardly from the closed position to the open position on the pivot pins and the bearings when the cremone locking means is unlocked.
The outer and inner frameworks of the access door have been generally assembled by screwing four similar elongated aluminum or rolled steel outer and inner framework elements, which may be extruded, drawn or similarly processed elements, together with corner members interposed between the adjacent and opposed ends of the outer and inner framework elements, or the outer and inner frameworks of the access door have been assembled by putting four framework elements in square and hammering the corner members into each inserting groove, previously formed in the extruding or drawing process, of both edges of two framework elements abutted with each other.
In the access door having the above-described construction, without keeping it under lock and key, it is possible that the cremone locking means may be loosened and the cover may be opened by an earthquake, and that the cover may be opened without permission for facilitating inspection and/or repair of facilities.
And in the above-mentioned assembling method, the work efficiency is not good; moreover the framework elements are not closely and accurately abutted with each other at the corners of the frameworks, and therefore the manufactured access doors may not be uniform.
Furthermore, it is generally desired that the inner framework with the cover plate can be removed from the outer framework after the inner framework is opened, for the convenience of facilitating inspection and/or repair of facilities, but in the conventional access doors the outer framework thereof cannot be removed in the above-mentioned way, or even if the conventional access doors have a construction by which the inner framework can be removed after the cover is opened, in the closed condition, the cover is easily taken off the outer framework by an upward pressing force thereon, thereby resulting in a danger that the cover may fall unexpectedly. Such conventional access doors are therefore lacking in safety.